1. Field of the Invention
The field of the present invention relates to ramps, a ramp weight-reducing assembly, and, more specifically, to a weight-reducing spring assembly, attached to a ramp, to reduce the weight required to be lifted by an operator when the operator manually raises the end of the ramp to an appropriate working level.
2. Description of the Related Art
Ramps, such as walk ramps, are often provided for loading and unloading products from vehicles, e.g., trucks, trailers, boats and aircraft. In most applications, and especially in trucks and trailers, the ramp is withdrawn from a stored position by hand and the ramp nose, i.e., near the end of the truck or trailer, is lifted by hand to the level of the unloading surface. Hooks on the ramp are subsequently aligned over and inserted into holes in the edge of the truck or trailer bed. The normal force from the weight of the ramp cooperates with the hooks and holes for securing the load bearing ramp against the load bearing floor of the truck for supporting cargo therefrom.
While the ramps can be constructed of light-weight aluminum, the ramps are principally designed for load bearing support and are often heavier than can be comfortably lifted by an operator. Consequently, because of the weight and leverage factors involved, the operator often must strain to lift the ramps up into the hook holes causing an undesirable burden for him or her. Ramps for many such vehicles under such conditions can be quite heavy when designed to support objects weighing as much as 1,700 lbs.
When not in use the ramps are typically stored in a carrier located below the vehicle floor. The space available for the ramps within carriers is limited to approximately the dimensions of the ramp which, when positioned laterally, slides into the carrier.
Attempts have been made to develop new ways of lifting the ramp. One such ramp lifting device, described in Gingrich, et al., U.S. Pat. No. 5,133,634, provides structure for elevating a ramp from an initial position to the floor height of a vehicle by hand. However, because one hand must be used with the lifting device to raise the ramp, the operator then has only one hand free with which to align the hooks over the hook holes.
In many cases, ramps, within the field of the invention, are used by relatively unskilled operators and without any instruction prior to use. Therefore, it would be desirable to use a device to reduce the weight of the ramp that the operator must lift without requiring the operator to be trained in new procedures for lifting and aligning the ramp for placement of the hooks in the hook holes. In addition, the ramp nose weight must be sufficient to provide the downward normal force which cooperates with the hooks and hook holes for securing the ramp against the vehicle floor for load bearing operation. Furthermore, such a device should not require any additional steps or additional assembly once it has been installed and therefore must fit within the ramp carrier with the ramp. Finally, such a device must be relatively simple to manufacture at a low cost and have a life cycle relatively equal to the life of a vehicle ramp.